The present invention relates to a manufacturing method of a diamond cutter, and more particularly to an invention in which a cutter base plate constituting a diamond cutter is formed so as to have a curved surface.
As is well known, cutting a road surface (asphalt) in a circular shape in order to form a manhole in a road, a hole for sticking up a pole or the like in a park, or the like is performed. For this purpose, a cutting apparatus in which a bit is mounted to a tip of a cylindrical casing has been conventionally used, however, since the equipment is large-scaled, a diamond cutter in which a diamond chip blade is mounted to an outer periphery of a circular cutter base plate has been gradually used. Paying attention to this diamond cutter, the circular flat diamond cutter has been conventionally manufactured by cutting a material having a comparatively high hardness in a circular shape by a laser beam cutting apparatus, applying a hardening and annealing process to the circular flat material, thereafter executing a so-called tensioning process as well as applying a grinding process, and finally attaching diamond chips to an outer periphery thereof intermittently with a fixed interval in accordance with a brazing. In the case of this circular flat diamond cutter, at a time of cutting the road surface in a circular shape for forming the manhole or the like, the cutting operation is performed by rotating the diamond cutter on its own axis and moving the diamond cutter around a center. However, there are problems such that a rotational oscillation is easily generated at a time of rotating on its own axis and moving around the center because the cutter base plate is flat, and it is hard to smoothly move around the center due to the flat cutter base plate.
Accordingly, in recent days, there has been used a diamond cutter comprising a circular cutter base plate and a diamond chip mounted on an outer periphery thereof, in which the cutter base plate is formed so as to have a curved shape between an axial hole and an outer shape, for example, formed in a parabolic antenna shape or a cup shape as a whole. For example, this is proposed in Japanese Unexamined Utility Model Publication No. 62-159510, the structure is made such that cutting the road surface in the circular shape in order to form the manhole on the road surface by using this is performed by moving the diamond cutter around the center while rotating the diamond cutter having the parabolic antenna shape mentioned above on its own axis, and the structure has an advantage that the rotational oscillation at a time of cutting is reduced, and it is possible to smoothly perform the cutting motion at a time of revolution.
However, in the case of the conventional art mentioned above, in order to form the cutter base plate for the diamond cutter so as to have the curved surface in parabolic antenna shape, a whole of the base plate has been formed in the parabolic antenna shape or the cup shape in accordance with a so-called scraping with using a material having a comparatively high hardness and further using a thick material.
Accordingly, in accordance with the conventional art mentioned above, since the base plate is formed by scraping the material having the comparatively high hardness so as to have the curved surface between the axial hole and the outer shape, there are problems that a stock utilization is low, a lot of trouble is taken for manufacturing, a lot of skill is required for a scraping process, and a manufacturing cost is high.